From: Justin Collins <justincollins@...>
Date: 2013-05-01T08:06:16+09:00
Subject: Re: is there any performance difference between Range#include? and Range#cover?

On 04/30/2013 02:58 PM, Edoardo Rossi wrote:
> On Tue, Apr 30, 2013 at 11:17 PM, Joel Pearson <lists@ruby-forum.com> wrote:
>> I'd expect cover to perform better in a benchmark, since it checks the
>> min-max rather than the entire range.
>>
>> --
>> Posted via http://www.ruby-forum.com/.
>>
>
> Humm...
>
> irb(main):010:0> require 'benchmark'
> => true
> irb(main):011:0> Benchmark.bm do |x|
> irb(main):012:1* x.report('include') { 10000000.times {
> (0..99).include?(rand(1000))}}
> irb(main):013:1> x.report('cover') { 10000000.times {
> (0..99).cover?(rand(1000))}}
> irb(main):014:1> end
>         user     system      total        real
> include  5.790000   0.000000   5.790000 (  5.802889)
> cover  5.830000   0.000000   5.830000 (  5.826916)
>
> Hope this helps... but maybe my benchmark is not accurate as it should be?
>
> e.
>


Both methods use the start/end of the range, but Range#include? performs 
some conversions (like calling `to_int`) while Range#cover? does a 
straight comparison.

By the way, the docs show this difference in the examples:

http://rdoc.info/stdlib/core/Range#cover%3F-instance_method
http://rdoc.info/stdlib/core/Range#include%3F-instance_method

-Justin